A rotary device containing a housing having a curved inner surface with a profile equidistant from a trochoidal curve, an eccentric mounted on a shaft disposed within the housing, a rotor mounted on the eccentric shaft which contains at least three faces, a partial bore located at the intersection of adjacent faces, and at least three rollers rotatably mounted within the partial bores of the roller. The rotor is comprised of a front face, a back face, a first side, a second side, and a third side. On each front and back face, between adjacent sides, an opening is formed.
In applicants"" U.S. Pat. No. 5,1131,551, there is disclosed and claimed a rotary device comprised of a housing comprising a curved inner surface with a profile equidistant form a trochoidal curve, an eccentric mounted on a shaft disposed within said first housing, a first rotor mounted on said eccentric shaft which is comprised of a first side, a second side, and a third side, a first partial bore disposed at die intersection of said first side and said second side, a second partial bore disposed at the intersection of said second side and said third side, a third partial bore disposed at the intersection of said third side and said first side, a first solid roller disposed fluid rotatably mounted within said first solid bore, a second solid roller disposed and rotatably mounted within said second partial bore, and a third solid roller disposed and rotatably mounted within said third pairtial bore. The rotor is comprised of a front face, a back face, a first side, a second side, and a third side, wherein a first opening is formed between and communicates between said front face and said first side, a second opening is formed between and communicates between said back face and said first side, wherein each of said first opening and said second opening is substantially equidistant and symmetrical between said first partial bore and said second partial bore, a third opening is formed between and communicates between said front face and said second side, a fourth opening is formed between and communicates between said back face and said second side, wherein each of said third opening and said fourth opening is substantially equidistant and symmetrical between said second partial bore and said third partial bore, a fifth opening is formed between and communicates between said front face and said third side, and a sixth opening is formed between and communicates between said back face and said third side, wherein each of said fifth opening and said sixth opening is substantially equidistant and symmetrical between said third partial bore and said first partial bore. Each of said first partial bore, said second partial bore, and said third partial bore is comprised of a centerpoint which, as said rotary device rotates, moves along said trochoidal curve. Each of said first opening, said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening has a substantially U-shaped cross-sectional shape defined by a first linear side, a second linear side, and an arcuate section joining said first linear side and said second linear side, wherein said first linear side and said second linear side are disposed with respect to each other at an angle of less than ninety degrees, and said substantially U-shaped cross-sectional shape has a depth which is at least equal to its width. The diameter of said first solid roller is equal to the diameter of said second solid roller, and the diameter of said second solid roller is equal to the diameter of said third solid roller. The widths of each of said first opening said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening are substantially the same, and the width of each of said openings is less than the diameter of said first solid roller. Each of said first side, said second side, and said third side has substantially the same geometry and size and is a composite shape comprised of a first section and a second section, wherein said first section has a shape which is different from said second section.
A similar patent, U.S. Pat. No. 6,301,898, issued to applicants"" on Oct. 16, 2001. This patent discloses and claims a rotary device comprised of a housing comprising a curved inner surface with a profile equidistant from a trochoidal curve, an eccentric mounted on a shalt disposed within said housing, a first rotor mounted on said ecceitric which is comprised of a first side, a second side, and a third side, a first partial bore disposed at the intersection of said first side and said second side, a second partial bore disposed at the intersection of said second side and said third side, a third partial bore disposed at the intersection of said third side and said first side, a first hollow roller disposed and rotatably mounted within said first solid bore, a second hollow roller disposed and rotatably mounted within said second partial bore, and a third hollow roller disposed and rotatably mounted within said third partial bore, wherein: (a) said rotor is comprised of a front face, said back face, said first side, said second side, and said third side, wherein: 1. a first opening is formed between and communicates between said front face and said first side, 2. a second opening is formed between and communicates between said back face and said first side, wherein each of said first opening and said second opening is substantially equidistant and symmetrical between said first partial bore and said second partial bore, 3. a third opening is formed between and communicates between said front face and said second side, 4. a fourth opening is formed between and communicates between said back face and said second side, wherein each of said third opening and said fourth opening is substantially equidistant and symmetrical between said second partial bore and said third partial bore, 5. fifth opening is formed between and communicates between said front face and said third side, and 6. a sixth opening is formed between and communicates between said back face and said third side, wherein each of said fifth opening and said sixth opening is substantially equidistant and symmetrical between said third partial bore and said first partial bore; (b) each of said first partial bore, said second partial bore, and said third partial bore is comprised of a centerpoint which, as said rotary device rotates, moves along said trochoidal curve; (c) each of said first opening, said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening has a substantially U-shaped crosssectional shape defined by a first linear side, a second linear side, and an arcuate section joining said first linear side and said second linear side, wherein: 1. said first linear side and said second linear side are disposed with respect to each other at an angle of less than ninety degrees, and 2. said substantially U-shaped cross-sectional shape has a depth which is at least equal to its width; (d) the diameter of said first hollow roller is equal to the diameter of said second hollow roller, and the diameter of said second hollow roller is equal to the diameter of said third hollow roller; (e) the widths of each of said first opening said second opening, said third opening, said fourth opening, said fifth opening, and said sixth opening arc substantially the same, and the width of each of said openings is less than the diameter of said first hollow roller; and (f) each of said first side, said second side, and said third side has substantially the same geometry and size and is a composite shape comprised of a first section and a second section, wherein said first section has a shape which is different from said second section. The entire disclosure of each of U.S. Pat. Nos. 5,431,551 and 6,301,898 is hereby incorporated by reference into this specification.
The compressors of U.S. Pat. Nos. 5,431,551 and 6,301,898, although substantial better than prior art compressors, exhibited dynamic losses in the port areas due to restricted flow areas. It is an object of this invention to provide a compressor which has lower port losses.
In accordance with this invention, there is provided a rotary positive displacement compressor assembly comprising a housing having a curved inner surface with a profile equidistant from a trochoidal curve, and eccentric mounted on a shaft disposed within said housing, a rotor mounted on said eccentric shaft which is comprised of a bore with an axial centerline, a front face, a back face, a first side, a second side, and a third side, a first partial bore disposed at the intersection of the first side and the second side, a second partial bore disposed at the intersection of said second side and said third side, a third partial bore disposed at the intersection of said third side and said first side, a first roller disposed and rotatably mounted within said first partial bore, a second roller disposed and rotatably mounted within said second partial bore and a third roller disposed and rotatably mounted within said third partial bore. In this assembly, a first opening is formed between and communicates between said front face and said first side, a second opening is formed between and communicates between said back face and said first side, a third opening is formed between and communicates between said front face and said second side, a fourth opening is formed between and communicates between said back face and said second side, a fifth opening is formed between and communicates between said front face and said third side, and a sixth opening is formed between and communicates between said back face and said third side. In the assembly, a first transverse rotor centerline extends through said first side, a second transverse rotor centerline extends though said second side, and a third transverse rotor centerline extends through said third side, provided that each of said first transverse rotor centerline, said second transverse rotor centerline, and said third transverse rotor centerline also extends through said axial centerline of said bore in said rotor. The first opening is comprised of a first opening centerline, said second opening is comprised of a second opening centerline, provided that said first opening centerline and said second opening centerline are each offset from said rotor transverse centerline by at least 0.1 inches and from about 0.x to about 4.x, wherein x is equal to the width of said opening. The third opening is comprised of a third opening centerline, said fourth opening is comprised of a fourth opening centerline, provided that said third opening centerline and said fourth opening centerline are each offset from said rotor transverse centerline by at least 0.1 inches and from about 0.x to about 4.x, wherein x is equal to the width of said opening. The fifth opening is comprised of a first opening centerline, said sixth opening is comprised of a second sixth centerline, provided that said fifth opening centerline and said sixth opening centerline are each offset from said rotor transverse centerline by at least 0.1 inches and from about 0.x to about 4.x, wherein x is equal to the width of said opening. In the assembly, the degree to which said first opening centerline, said third opening centerline, and said fifth opening centerline are offset from said rotor transverse centerlines are the same; and the degree to which said second opening centerline, said fourth opening centerline, and said sixth opening centerline are offset from said rotor transverse centerlines are the same.